Tuesday, December 13, 2016

Walking Water

If we drop a water droplet on a surface of water, it bounces for a few times before it merges itself to the water surface. This event is what we call "Coalescence" and it is natural for water to merge together and grow larger in volume after merging. The interesting fact here is that the water droplet had to bounce before it gets totally merged. The video above shows a drop of water in slow motion. As it travels down, there is air resistance being compressed between the water surface and the water droplet. This air resistance causes the water droplet to bounce back up and goes down again. This goes on until the water droplet's force is stronger than the air resistance.

Here is another video where we can technically levitate a water droplet using air resistance.

We notice in the experiment above that we can use sound to float water droplets in the air. As we know, sound travels through air and it brings with them an amount of force depending on the frequency. The experiment shows producing a sound with a force heavier than the water droplet which makes it to stay floating in the air.